Optical characteristics of Bi12SiO20 single crystals by spectroscopic ellipsometry

Işık, Mesut; Delice, S.; Nasser, Hisham; Gasanly, Nizami; Darvishov, N.H.; Bagiev, V. E.

doi:10.1016/j.mssp.2020.105286

Cited by 19 publications

(6 citation statements)

References 32 publications

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“…constituting discrete MO 4 tetrahedra, separated by Bi-O frameworks to form a body centered cubic lattice with space group I 23 1 – 6 . These Bi rich compounds are attractive materials for practical applications owing to their photoconductive, photorefractive, piezoelectric, pyroelectric and nonlinear optical (NLO) properties 7 . The catalytic properties encourage potential use of these compounds for photocatalytic applications in organic effluent treatment and water splitting.…”

Section: Introductionmentioning

confidence: 99%

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Vavilapalli

Melvin

Bellarmine

et al. 2020

Sci Rep

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Ideal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

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Section: Introductionmentioning

confidence: 99%

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Vavilapalli

Melvin

Bellarmine

et al. 2020

Sci Rep

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“…In literature the reported bandgap energy of BSO varies between 2.2 and 3.4 eV. [ 13,20,44–46 ] The plot shows that the bandgap energy of BSO decreases with the incorporation of Cr in the lattice (Table 2). To examine the correlation between the effect of Cr doping on the lattice parameter and the bandgap energy, both are shown in Figure 8 as a function of Cr concentration.…”

Section: Resultsmentioning

confidence: 99%

Crystal Interface Control at Low Thermal Gradient and Investigation of the Effect of Cr on the Crystal Structure and Optical Properties of Bismuth Silicate

Bhaumik

Viswanathan

Bhatt

et al. 2021

Physica Status Solidi (b)

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Sillenite structure crystals (general composition Bi 12 XO 20 , X ¼ Si, Ge, and Ti with space group I23) posses a number of properties important for practical applications. [1,2] They are characterized by XO 4 tetrahedra located at the center and corners of its cubic unit cell. These XO 4 tetrahedra are linked with stereochemically active 6s 2 lone electron pair of Bi 3þ via BiO 5 octahedra. [3][4][5] This, along with the absence of inversion symmetry, is the source of outstanding electrical and optical properties suitable for photorefractive applications. [1][2][3][4][5] Among sillenites, bismuth silicate (Bi 12 SiO 20 , BSO) is a technologically important material as it exhibits large electro-optic and photoconductive effects, which make it suitable for optical switches, optics-based electric field sensors, holographic storage, and photorefractive devices. [6][7][8][9][10][11][12][13][14] It is used for two-wave mixing, four-wave mixing, phase conjugation, real-time holography, optical data storage, optical computing, and electro-optical modulation. [7,8] It has been reported that the photorefractive property of BSO is enhanced significantly on doping with metals like Cr, Fe, Mg, Ru, etc. [8,[15][16][17][18][19][20][21][22][23][24][25][26][27] Though most of these dopants make material sensitive to photorefraction in the visible region, especially around 500 nm, that is, 2.5 eV, practical feasibility prefers the region near the infrared (1.5À2 eV), mainly because of the availability of compact laser diodes in this region. [28] Cr doping shifts the photorefractive sensitivity of BSO to the near-infrared region and therefore makes it a potential material for applications like optical image processing, holographic interferometry, optical storage, and phase conjugation. In literature, there are reports on the growth of Cr-doped BSO crystal and investigations on the photorefractive effect, dielectric property, optical activity, Faraday effect, etc. [15][16][17][18][19][20][21][22][23][24] For the growth of the crystal, Czochralski technique has been used as BSO is a congruently melting compound. [25,26] It is known that the devices mentioned earlier require crystals with a low dislocation density and high optical homogeneity. [29] One of the important aspects of growth of crystals having low dislocation density is to grow the crystal with a flat-ish crystalÀmelt interface. [26] A few studies have been reported on undoped BSO for relatively higher thermal gradient. [30,31] However, to obtain large-sized good quality crystal of BSO, a lower thermal gradient is favorable. [32] In view of this, one of the objectives of the work is investigate the effect of the growth condition on the interface shape control of the Cr:BSO crystal when grown along 〈110〉 in the lower axial

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“…Since we had chance to perform experiments in the below 80 K temperature region which has not been reached in previous papers, three shallow levels at 0.09, 0.15 and 0.18 eV were reported for the first time. The band gap energy of the used BSO crystal in the present paper was determined from analyses of transmission and ellipsometry measurements as 2.48 eV [19] and 3.25 eV [14], respectively. The smaller band gap energy was associated with defect centers.…”

Section: Resultsmentioning

confidence: 99%

“…The fascinating properties of the sillenite group members make them preferable materials in various electronic applications like hologram recording, photocatalysts, optical data processing and interferometry [7][8][9][10][11]. Bi 12 SiO 20 (abbreviated as BSO) belongs to sillenite family and its high electrical resistivity, wide band gap energy and high photocatalytic activity characteristics take remarkable attention in related technological applications [12][13][14]. BSO has cubic crystalline structure with lattice constant of a=1.0105 nm and its band gap energy was reported as ∼3.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of defect levels in Bi₁₂SiO₂₀ single crystals by thermally stimulated current measurements

Isik¹,

Delice²,

Gasanly³

2021

Phys. Scr.

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Bi12SiO20 (BSO) single crystal belongs to the sillenite semiconducting family known as defective compounds. The present paper investigates the defect centers in BSO grown by Czochralski method by means of thermally stimulated current (TSC) measurements performed in the 10-260 K range. The TSC glow curve obtained at heating rate of β = 0.1 K/s presented several peaks associated with intrinsic defect centers. The activation energies of defect centers were revealed as 0.09, 0.15, 0.18, 0.22, 0.34, 0.70 and 0.82 eV accomplishing the curve fit analyses method. The peak maximum temperatures and orders of kinetics of each deconvoluted peak were also determined as an outcome of fitting process. TSC experiments were expanded by making the measurements at various heating rates between 0.1 and 0.3 K/s to get information about the heating rate dependent peak parameters.

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Optical characteristics of Bi12SiO20 single crystals by spectroscopic ellipsometry

Cited by 19 publications

References 32 publications

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Crystal Interface Control at Low Thermal Gradient and Investigation of the Effect of Cr on the Crystal Structure and Optical Properties of Bismuth Silicate

Investigation of defect levels in Bi₁₂SiO₂₀ single crystals by thermally stimulated current measurements

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Optical characteristics of Bi12SiO20 single crystals by spectroscopic ellipsometry

Cited by 19 publications

References 32 publications

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Crystal Interface Control at Low Thermal Gradient and Investigation of the Effect of Cr on the Crystal Structure and Optical Properties of Bismuth Silicate

Investigation of defect levels in Bi12SiO20 single crystals by thermally stimulated current measurements

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Investigation of defect levels in Bi₁₂SiO₂₀ single crystals by thermally stimulated current measurements